Technique for protecting photonic devices in optoelectronic packages with clear overmolding

ABSTRACT

This disclosure describes a clear overmolding cap for protecting the photonic devices in optoelectronic packages from damage due to handling, module assembly, board assembly, and environmental exposure in field applications. The overmolding of the devices with a clear mold cap or similar material also provides a standoff for optical fibers positioned next to the active facets. The photonic devices are attached to a substrate, which may be flexible that has electronic traces that allow the photonic devices to be connected to an external device such as a semiconductor device. A technique for manufacturing the overmolding cap using a mold die system in combination with a rigid carrier is also disclosed. The rigid carrier is used to maintain the shape of the substrate during the molding process. The proposed method applies to photonic devices used in optoelectronic packages that can serve as transceivers, transmitters, or receivers.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a Divisional application of prior U.S. Application No.09/957,936, entitled “TECHNIQUE FOR PROTECTING PHOTONIC DEVICES INOPTOELECTRONIC PACKAGES WITH CLEAR OVERMOLDING”, filed on Sep. 21, 2001and now U.S. Pat. No. 7,001,083, which is incorporated herein byreference and from which priority under 35 U.S.C. § 120 is claimed.

This application is related to U.S. patent application Ser. No.09/922,598 filed on Aug. 3, 2001, and entitled “TECHNIQUES FOR JOININGAN OPTO-ELECTRONIC MODULE TO A SEMICONDUCTOR PACKAGE,” and to U.S.patent application Ser. No. 09/568,094, filed on May 9, 2000, andentitled “DEVICE AND METHOD FOR PROVIDING A TRUE SEMICONDUCTOR DIE TOEXTERNAL FIBER OPTIC CABLE CONNECTION,” and to U.S. patent applicationSer. No. 09/922,601, filed on Aug. 3, 2001, and entitled “OPTICALSUB-ASSEMBLY FOR OPTO-ELECTRONIC MODULES,” and to U.S. patentapplication Ser. No. 09/922,357, filed on Aug. 3, 2001, and entitled“OPTOELECTRONIC PACKAGE WITH DAM STRUCTURE TO PROVIDE FIBER STANDOFF,”and to U.S. patent application Ser. No. 09/922,946, filed on Aug. 3,2001, and entitled “OPTOELECTRONIC PACKAGE WITH CONTROLLED FIBERSTANDOFF,” the content of which is hereby incorporated by reference.

BACKGROUND OF THE INVENTION

The present inventions relate generally to mechanisms sealing andprotecting photonic devices in optoelectronic packages. Moreparticularly, the photonic device is overmolded with a clear moldingmaterial. When appropriate, the clear molding material may be used tocontrol the standoff distance between an optical fiber and the photonicdevice.

Optical networks have a wide variety of applications and are, forexample, widely used within the telecommunications, data transmissionand high speed networking industries. The optical devices used toconvert electrical signals into light signals and light signals intoelectrical signals are key components in any such optical network.Generally, such devices include one or more photonic elements (e.g.detectors and/or laser emitters) together with the electronic circuitrynecessary to drive the photonic elements (e.g., receiver, transmitter ortransceiver circuitry). Although a wide variety of optical transceiverdevices are currently commercially available, there are alwayscontinuing efforts to improve their design and functionality as well asto lower their production costs.

At the time of this writing, most commercially available photonicdevices are placed in sealed packages such as TO (transistor outline)metal cans or ceramic chip carriers. A transparent glass or plasticwindow is then positioned over the active area of the photonic device.The die is typically adhered to the carrier and electrically connectedto traces on the carrier using wire bonding.

One issue that is fundamental to the design of any photonic device isthe desire to (relatively) efficiently optically couple each activefacet (i.e., emitter or receiver) to its associated optical fiber. Whenphotonic devices are packaged in metal cans or ceramic carriers, thereis an inherent standoff distance between the optical fiber or fiberbundle and the active facets of the devices. Typical standoff distancesin currently available packages tend to be in the range of 1–5 mmdepending upon the type of packaged used. At these distances, it becomesimportant to collimate the optical fibers to insure good opticalcoupling between the fibers and the photonic elements. Typically,collimation is accomplished by providing a simple lens at thetermination of the optical fiber.

Although the described packaging techniques work well, they arerelatively expensive to produce. Accordingly, there are continuingefforts to provide improved optical component packaging techniques thathelp reduce the size and costs of the optical components.

BRIEF SUMMARY OF THE INVENTION

This invention describes a method of protecting the photonic devices inoptoelectronic packages from damage due to handling, module assembly,board assembly (e.g., during surface mount reflow), and environmentalexposure in field applications. The overmolding of the devices with aclear epoxy mold compound or similar material can also provide astandoff for optical fibers positioned next to the active facets. Closeproximity of fiber and facet provides for enhanced optical couplingefficiency. The proposed method applies to photonic devices used inoptoelectronic packages that can serve as transceivers, transmitters, orreceivers.

One aspect of the present invention pertains to an optoelectronicpackage which includes a substrate, a photonic device carried by thesubstrate, the photonic device having an active facet thereon, anoptical fiber in optical communication with the active facet on thephotonic device, and an optically clear cap that is molded over thephotonic device to cover the active facet of the photonic device.

As a method, one embodiment of the present invention includes at least amethod of manufacturing an optoelectronic device involving theoperations of attaching a photonic device directly or indirectly to aflexible substrate, attaching the flexible substrate onto a rigidcarrier, whereby the rigid carrier maintains the flexible substrate in afixed position, placing the flexible substrate and the rigid carrieronto a lower mold such that the photonic device is lowered into amolding cavity within the lower mold, and forming an optically clear capon the base substrate by flowing a clear resin into a molding cavity ofa molding die.

These and other features and advantages of the present invention will bepresented in more detail in the following specification of the inventionand the accompanying figures, which illustrate by way of example theprinciples of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention, together with further advantages thereof, may best beunderstood by reference to the following description taken inconjunction with the accompanying drawings in which:

FIG. 1 illustrates a perspective view of a clear overmolding cap thatencapsulates a photonic array device, which is attached to a substrate,according to one embodiment of the present invention.

FIG. 2A illustrates a top plan view of a clear overmolding cap, whichencapsulates two photonic array devices, according to one embodiment ofthe invention.

FIG. 2B illustrates a side plan view of the overmolding cap of FIG. 2A.

FIG. 3 illustrates a side plan view of the optical interface region ofan optoelectronic package formed in accordance with one embodiment ofthe invention.

FIG. 4 illustrates a perspective view of one embodiment of a moldingsystem for making the overmolding cap of the present invention.

FIG. 5 illustrates a side plan view of the mold system with a flexiblesubstrate attached to a rigid carrier that is placed between the moldsystem.

FIG. 6 illustrates a top perspective view of the substrate mounted ontothe rigid carrier of FIG. 5, after overmolding caps have been formed.

FIG. 7 illustrates a flow diagram of the process for manufacturing aclear overmolding cap over a photonic device, according to oneembodiment of the present invention.

FIG. 8 illustrates the detailed operations of using the release filmlayer.

FIG. 9 illustrates an optoelectronic package incorporating theovermolding cap in accordance with one embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention will now be described in detail with reference toa few preferred embodiments thereof as illustrated in the accompanyingdrawings. In the following description, numerous specific details areset forth in order to provide a thorough understanding of the presentinvention. It will be apparent, however, to one skilled in the art, thatthe present invention may be practiced without some or all of thesespecific details. In other instances, well known operations have notbeen described in detail so not to unnecessarily obscure the presentinvention.

The present invention pertains to a clear overmolding used to protect aphotonic array device from structural and environmental damage. Theovermolding encapsulates a photonic array and the wirebonds that connectthe photonic array to an electronic substrate. In addition to protectingthe photonic array, the overmolding provides a standoff distance betweenthe photonic device and optical fibers to be connected thereto byproviding a surface to which to register the optical fibers.

FIG. 1 illustrates a perspective view of a clear overmolding cap 100that encapsulates a photonic array device 102, which is attached to asubstrate 104, according to one embodiment of the present invention. Thephotonic device 102 contains an array of circuits that are either lasersor detectors. The active areas, or active facets 106, and the anodes 108of the photonic device 102 are on the top surface of the photonic device102. The anodes 108 are connected to the contact pads of the electricaltraces 110 through bonding wires 112. The overmolding cap 100encapsulates and protects photonic array device 102 and bonding wires112. The cathode of the photonic device 102 is typically located on theopposite surface of the photonic device 102 containing the anodes 108and the active facets 106. In this particular embodiment, the bondingwires 112 are ball bonded to the electrical traces 110 and stitch bondedto the anodes 108. This technique, referred to as reverse wirebonding,allows the loop height of the bonding wire to be kept to a minimum. Thelower loop height allows the overall height of the overmolding cap 100to be minimized because a shorter cap can be used to encapsulate bothphotonic device 102 and bonding wire 112. Ultimately, the lower heightof the cap 100 allows an optical fiber to be placed as close as possibleto the active facets 106 of the photonic device 102 since theovermolding cap 100 acts as a standoff for the fiber or fiber bundle. Aswill be seen in FIG. 3, optical fibers are placed directly in contactwith the overmolding cap.

In the embodiment shown in FIG. 1, the thickness of the overmolding cap100 in the region directly over the active facet 106 is approximately0.1 mm. Theoretically, an optical fiber or fiber bundle can bepositioned directly against the coating, keeping the standoff atapproximately 100 microns.

The clear overmolding cap 100 acts as a protective coating over theentire photonic exposed areas (top active facets and all four sides ofthe devices or array). Protection can be against a number of factorssuch as damage to the passivation during the pick and place step, boardassembly operations, thermal expansion, and field operations. Bycovering the wirebonds 112 connecting the photonic device 102 to thesubstrate 104, the overmolding cap 100 prevents damage to the fragilewirebonds. Firm encapsulation of the wires ensures that the devices andmodules are protected against damage induced by vibration, impact, andshock.

The top surface of the overmolding cap 100 is slanted at an angle withrespect to the top surface of the photonic device 102. The slant angleis approximately 7–8 degrees. This angle reduces the amount of backreflection between a laser photonic device and an optical fiber placedin optical communication with the photonic device. Back reflection isthe reflection of transmitted light back towards the light source. Slanton the overmolding cap is the best mode for preventing back reflectionfor transmitter photonic arrays. The slant angle is not as critical fordetector photonic arrays. Reducing back reflection increases the opticalcoupling efficiency. In alternative embodiments the slant angle may beconfigured at various other angles.

Since the top surface of the overmolding cap 100 has a slanted topsurface, the cap 100 is thicker at one end relative to the opposite endof the cap. It is preferable to orient the cap 100 such that the thickerend of the cap encapsulates the bond wire 112. In this way, the overallthickness (and height) of the cap 100 can be kept to a minimum.

The encapsulating material forming the overmolding cap 100 is an indexmatching epoxy molding compound, but could be any similar unfilledthermoset including reactive silicone gels with index matchingcharacteristics. Index matching refers to the fact that the index ofrefraction of the overmolding cap material is selected to match theindex of refraction for photonic device 102, the atmosphere in betweenthe fiber and the overmolding cap, and the optical fiber. Optimizationof the index of refraction values also serves to minimize backreflection. The index of refraction can be selected with the aid of asoftware modeling program. Depending upon the specific implementation ofthe invention, the index of refraction of the overmolding is selected tomatch, as best as possible, the index of refraction of the optical fibercore, the photonic array, and air. A typical index of refraction for theovermolding is in the range of approximately 1.45 to 1.51.

Preferably, the material forming the overmolding cap 100 does notcontain fillers. Athough the fillers would reduce the coefficient ofthermal expansion of the compound, which is desirable for thermalshock/thermal cycling performance, material clarity for lighttransmission would be impacted.

The traces 110 on substrate 104 provide a pathway for connecting theanodes 108 to an electrical device, such as a semiconductor die,suitable for driving the photonic device 102. The outer electricaltraces 114 provide pathways for connecting the cathode of the photonicdevice 102 to an external electrical device. In certain embodiments ofthe invention, the substrate 104 is a thin, flexible material.

In alternative embodiments, the overmolding cap 100 can cover variousphotonic devices and configurations thereof on a substrate. Forinstance, the photonic device could be rotated such that the activefacets 106 are in a plane perpendicular to the top surface of thesubstrate 104. Such a rotated photonic device can be set within thesubstrate by placing it in an etched groove within the substrate andconnected to the electrical traces of the substrate through conductiveadhesive or solder. For more detail describing such a configuration,please refer to U.S. patent application Ser. No. 10/165,548.

FIG. 2A illustrates a top plan view of a clear overmolding cap 200,which encapsulates two photonic array devices 202 and 204, according toone embodiment of the invention. The photonic array devices 202 and 204are mounted on a substrate 206 that has electrical traces 208. Each ofphotonic devices 202 and 204 can be either light emitters or detectors.When device 202 and device 204 are an emitter and a detector,respectively, the photonic module can be used to make an opticaltransceiver. Active facets 207 and anode pads 209 are seen on the topsurfaces of each of the photonic devices 202 and 204. Bond wires 210connect each of the anode pads 209 to the contact pads 212 of theelectrical traces 208.

FIG. 2B illustrates a side plan view of the overmolding cap 200 of FIG.2A. FIG. 2B shows that the bond wire 210 has been ball bonded to thecontact pad 212 of the electrical trace and stitch bonded to the anodepad 209 of photonic device 202. FIG. 2B also illustrates the preferredembodiment in which the bond wire 210 is encapsulated within the thickerportion of the overmolding cap 200. The thicker portion of the cap 200being the half of the cap having the taller height, H₁, due to theupward slant of the top surface of the cap 200. Thickness, t₁, is thethickness of the cap 200 over the region of the active facet 207. Inthis embodiment, t₁ is approximately 0.1 mm.

FIG. 3 illustrates a side plan view of the optical interface region 302of an optoelectronic package 300 formed in accordance with oneembodiment of the invention. In the illustrated embodiment, a photonicdevice die 304 is mounted and electrically connected to a substrate 306such that the active facet (active region) of the photonic device 304 isexposed outward toward an optical fiber 308. An optically clear cap 310is formed on the substrate to serve as a registration surface for theoptical fiber. During assembly, a cladding portion of the optical fiber312 is brought into contact with the cap 310 so that the cap effectivelydefines the standoff distance between the substrate 306 and the facet ofthe photonic device 304. The inner core 314 of the optical fiber 308 isaligned with the active facet of the photonic device 304. Not shown inFIG. 3 are the various other mechanisms, pins, etc. that are used tosecure the optical fiber to the cap 310.

The substrate 306 has one or more conductive traces (not shown) thereon.The photonic device may be electrically coupled to the conductivetrace(s) by any suitable connection technique. In the embodiment shownbonding wire 316 is used. However, it should be appreciated that a widevariety of other suitable techniques, including (but not limited to)TAB, direct soldering (e.g. “flip chip” type mounting), and conventionalpackage mounting techniques (e.g. soldering, pins, etc.) can readily beused in particular implementations.

Now the technique for forming the overmolding cap of the presentinvention will be described. FIG. 4 illustrates a perspective view ofone embodiment of a molding system 400 for making the overmolding cap ofthe present invention. Molding system 400 includes a top mold 402 and abottom mold 404. Bottom mold 404 contains four cavities 406 having theoutline of the overmolding cap that is intended to be formed. Forexample, if the overmolding cap is to have a slanted top surface, thenthe bottom surface of the mold cavities 406 must have a slanted bottomsurface. The surface of the mold cavities 406 must be very smooth toimpart the overmolding with a smooth surface. In some embodiments, thesurface of the cavities are provided a layer of metal, such as polishedplated nickel, which gives the cavities a smoother surface. Runners 408are channels within the bottom mold 404 that distribute the clearmolding compound to the respective mold cavities 406. Mold materialflows from the hole 410 in the top mold, down into the pot 412, fromwhich the mold material then flows into each of the runners 408. Asubstrate containing photonic devices that are attached thereto isplaced onto the bottom mold 406 so that the photonic devices fall withineach of the mold cavities 406. Overmold caps are formed when the moldcavities 406 are filled with overmold material or resin. The upper mold402 is lowered onto the substrate so to secure the substrate and applypressure and heat needed to fully form the cap. The flexible substrateused to attach the photonic arrays can be designed to be sufficientlythick to avoid sagging or crimping while clamped inside the hot mold.This can be achieved, for instance, by adding to the standard polyimidecore (50 micron) one or two layers of copper. When two copper layers areused, both sides of the substrate are used. Indexing pins 414 protrudefrom the lower mold 404 to mate with indexing holes in the substrate soto properly align the two components and to secure the substrate duringthe molding process. Upon molding and post-curing, the flexiblesubstrate and associated carrier can be sawed and singulated into unitsfor further processing.

To obtain the optimum optical transmission qualities of the overmolding,voids within the overmolding must be prevented during the moldingprocess. To prevent voids, overmolding material is injected into themold cavities at a very slow rate. The mold system 400 facilitates highvolume manufacturing of the overmolding caps formed on substrates. Theconcept of system 400 can be extended to a larger number of cavitiesthat suit the needs for high volume throughput.

FIG. 5 illustrates a side plan view of the mold system 400 with aflexible substrate 500 attached to a rigid carrier 502 that is placedbetween the mold system 400. The rigid carrier 502 is an alternativetechnique for maintaining the shape of the flexible substrate 500throughout the molding, die attach, wirebonding and other handlingprocesses. The advantage of the rigid carrier 502 is that the rigidcarrier will allow extendability to multi-cavity tools without theconcern for loose tolerances obtained with a flexible substrate.Furthermore, the carrier will also provide more precision in theindexing holes compared to holes made in a thin flexible substrate.

The carrier 502 can be made out of FR4 (printed circuit boardepoxy/fiberglass material), a polymer, or a thick copper layer. Theflexible substrate 500 has attached photonic devices 504 that areconnected to the substrate 500 with bond wires 506. The substrate 500 isattached to the rigid carrier 502 in selected areas between each of thephotonic devices 504 with adhesive material 508. The adhesive material508 is positioned to allow for both the substrate and the rigid carrier502 to be cut into individual pieces after the molding of the caps arecompleted. FIG. 6 illustrates a top perspective view of the substrate500 mounted onto the rigid carrier 502 of FIG. 5, after overmolding caps600 have been formed over the photonic devices 504. Photonic devices 504are set upon and connected to the electrically conductive circuitpatterns 602 with bonding wires 604. Indexing holes 510 in the substrateare illustrated. However, in alternative embodiments, the indexing holes510 are preferably formed in the rigid carrier 502.

To facilitate the molding process, a release film layer can be used tocoat the surface of the mold cavities 406. The overmolding materialcontains no fillers because of the clear quality required for lighttransmission. Therefore the overmolding has lower viscosity and has agreater tendency to flow outside of the mold cavities during the moldingprocesses. This overflow causes undesirable flash areas to form on thesubstrate 500. One method of preventing flash is to utilize a releasefilm layer that is placed on the bottom mold 404 so that it conforms tothe shape of the cavities 406. This film is compressible such that whenthe top and bottom mold dies are pressed together, the film iscompressed and causes each of the mold cavities to be more completelysealed. The sealed cavities now do not allow overmolding material tooverflow and cause flash to form. In addition to facilitating a betterseal within each of the cavities 406, the release film prevents contactbetween a molding resin and the cavity surface of the mold and canfacilitate heat transfer between the mold and the overmold material toaccelerate manufacturing processes. Suction is required from air ventsin the bottom mold 404 so to suck the release film to conform to theshape of the cavities. See U.S. Pat. Nos. 5,891,384 and 5,891,483, whichare hereby incorporated by reference.

FIG. 7 illustrates a flow diagram 700 of the process for manufacturing aclear overmolding cap over a photonic device, according to oneembodiment of the present invention. The process begins with operation702 wherein photonic devices are attached to a substrate. The photonicdevices are adhesively attached and electrically connected to theelectrical traces on the substrate with bond wires. From operation 702,two alternative techniques can be employed. The first technique is thatof operation 704 wherein the substrate is attached to a rigid carrier,which functions to maintain the shape of the substrate during themolding process. In this case, the next operation 706 represents thealigning of the indexing holes on the surface of the rigid carrier withthe indexing pins of the top mold. Alternatively, the second techniquedoes not employ the rigid carrier. In this case, as shown in operation708, the indexing holes formed in the substrate itself are aligned withthe indexing pins of the bottom mold.

In operation 710, the release film layer is applied to the moldingsystem so that a better seal within each of the cavities can beachieved. As mentioned above, the release film layer assists inpreventing flash, protects the mold cavities from contact from theovermolding material and assists in the heat transfer between the moldsystem and the overmolding material. FIG. 8 illustrates the detailedoperations of using the release film layer. In FIG. 8, the operation 802shows that the first step of using the release film is to apply therelease film layer to the bottom mold. Then in operation 804, air issucked out of the cavities to assist the release film layer inconforming to the shape of the cavities. It is noted that the use of therelease film layer is an optional process. The release film can be ofdifferent thickness ranging from 2 to 4 mils (50 to 100 microns).Selection of the right thickness needs to be done in conjunction withthe mold tooling design (e.g., cavity depth, runner depth, gate, etc.)so to ensure that the correct part dimensions can be obtained withinspecified tolerances. Potential materials that can be used for therelease film can include polyimide (PI) or polytetrafluoroethylene(PTFE).

Then in operation 712, the top mold is lowered onto the bottom mold tosecure the substrate (and rigid carrier) between the two molds. Inoperation 714, molding material is injected into the molds through thehole in the top mold and through the runners formed in the bottom mold.In operation 716, the molding material is given time to cure. Inoperation 718, the substrate with the formed overmolding caps areremoved from the top and bottom mold. In operation 720, a post-curingprocess allows the overmolding caps to further cure. In operation 722,the substrate, and carrier if used, are singulated into individualsubstrate/cap modules. These modules can then be used in combinationwith a semiconductor device to form an optoelectronic module.

Referring next to FIG. 9, an optoelectronic package 900 in accordancewith another embodiment of the invention will be described. In theillustrated embodiment, a flexible substrate material 902 havingconductive traces (not shown) thereon is supported by support structure904. A photonic device (die) 906 is mounted and electrically connectedto the flexible substrate 902 such that the facet (active region) of thephotonic device is exposed outward towards the optical fiber 908. Anoptically clear cap 909 is formed over the photonic device 906 anddetermines the standoff of the fiber 908 from the substrate 902. Theoptical interface region 910 in this embodiment may take a form similarto the interface region 302 illustrated in FIG. 3. In this example, oneor more bond pads on the die are electrically coupled to one end of theflexible substrate. The flexible substrate is wrapped around one cornerof the optical base 904 and is electrically coupled to a separate die912 that includes suitable circuitry to drive the photonic device 906.The illustrated structure is described in more detail in co-pendingapplication Ser. No. 10/165,553.

Of course, the number of emitters or receivers on a particular devicecan be widely varied to meet the needs of a particular application. Inmany multi-channel applications, it is desirable to separate theemitters from the receivers in different chips. This is primarily due tothe nature of electrical cross-talk between the transmitter and receivercircuitry. However integrated transceivers can readily be provided aswell.

While this invention has been described in terms of several preferredembodiments, there are alterations, permutations, and equivalents, whichfall within the scope of this invention. It should also be noted thatthere are many alternative ways of implementing the methods andapparatuses of the present invention. It is therefore intended that thefollowing appended claims be interpreted as including all suchalterations, permutations, and equivalents as fall within the truespirit and scope of the present invention.

1. A method of manufacturing an optoelectronic device comprising:attaching a photonic device directly or indirectly to a flexiblesubstrate; attaching the flexible substrate onto a rigid carrier,whereby the rigid carrier maintains the flexible substrate in a fixedposition; placing the flexible substrate and the rigid carrier onto alower mold such that the photonic device is lowered into a moldingcavity within the lower mold; and forming an optically clear cap on thebase substrate by flowing a clear resin into a molding cavity of amolding die.
 2. A method of manufacturing an optoelectronic device asrecited in claim 1 wherein the molding cavity of the mold has a bottomsurface that is slanted at an angle approximately between 7–8 degrees.3. A method of manufacturing an optoelectronic device as recited inclaim 1 further comprising: lowering a top mold onto the rigid carriersuch that the flexible substrate is firmly secured between the top andbottom mold and photonic device is sealed within the molding cavity. 4.A system for manufacturing an optoelectronic package comprising: aflexible substrate having at least one electrically conductive tracethereon; a photonic device carried by the base substrate, the photonicdevice having an active facet and at least one bond pad thereon; a rigidcarrier that supports the flexible substrate such that the rigid carriermaintains the flexible substrate in a fixed position; a lower moldhaving a molding cavity, which receives the photonic device, the moldingcavity configured to be filled with a clear resin material that willharden and form a optically clear cap that covers the photonic device;and an upper mold configured to press the rigid carrier and the flexiblesubstrate against the lower mold such that a good seal can be createdbetween a contact region between the flexible substrate and the moldingcavity.
 5. A system for manufacturing an optoelectronic package asrecited in claim 4 wherein the lower mold has a plurality of moldingcavities, each cavity configured to receive at least one photonicdevice.
 6. A system for manufacturing an optoelectronic package asrecited in claim 4 wherein the molding cavity has a slanted bottomsurface such that the optically clear cap to be formed will have aslanted top surface.